The purpose of this project is to study the regulation of the globin genes at the molecular level. The approach is to identify regulatory factors which influence globin gene expression. Evidence for the existence of positive and negative regulatory factors in mouse erythroleukemia cells and in nonerythroid cytoplasms, respectively, have been found. Attempts are being made to isolate, purify and characterize these factors. BIBLIOGRAPHIC REFERENCES: Gopalakrishnan, T.V., Thompson, E.B., and Anderson, W.F.: Extinction of hemoglobin inducibility in Friend erythroleukemia cells by fusion with cytoplasm of enucleated mouse neuroblastoma or fibroblast cells. Proc. Natl. Acad. Sci. USA 74: 1642-1646, 1977.